Chemical control of salt cedar (Tamarix spp.) and Russian olive (Elaeagnus angustifolia L.) has had varying degrees of success. Some non-selective herbicides cause unacceptable injury to desirable species or do not control invasive species under the canopy. Aminopyralid (Milestone®) controls many invasive herbaceous broadleaf weeds, but control of salt cedar and Russian olive has not been fully explored. Experiments were established to assess the efficacy of various aminopyralid containing products and aminopyralid and triclopyr (Garlon 3A^ or Garlon 4 Ultra) mixtures on these plants. Treatments included triclopyr amine and triclopyr ester at various rates plus aminopyralid at 120 g ae/ha (0.l1 lbs ae/acre) and Milestone® VM Plus at 9.6 L/ha (1 gal/acre) [triclopyr amine at 1.12 kg ae/ha (1 lb ae/acre) and aminopyralid 120 g ae/ha (0.11 lb ae/acre)]. At 326 days after application, 3.3 kg ae /ha (3 lbs ae/acre) triclopyr ester plus 120 g ae/ha aminopyralid provided excellent control (98%) of Russian olive and salt cedar (94%), similar to efficacy of imazapyr at 1.12 kg ae/ha (1 lb ae/acre). Triclopyr + aminopyralid treatments caused little to no grass injury (0 to 5%) compared to the imazapyr treatments (50 to 85%). Milestone® VM Plus at 9.6 L/ha provided 91% control of salt cedar and no grass injury. Adding aminopyralid to either the triclopyr amine or triclopyr ester was synergistic and provided increased control of Russian olive and salt cedar thus providing another option for controlling these species without significant injury to desirable understory vegetation.
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Citation: SALT CEDAR AND RUSSIAN OLIVE CONTROL WITH AMINOPYRALID CONTAINING HERBICIDE TREATMENTS. Byron Sleugh, Mary Halstvedt, Chad Cummings, Vanelle Peterson, Dow AgroSciences, Indianapolis, IN; and Robert G. Wilson, University of Nebraska Panhandle Research Center, Scottsbluff, NE.